A Multicenter, Randomized, Double Blind, Placebo Controlled Study to Assess the Long-Term Efficacy and Safety of Prolonged Release Fampridine (BIIB041) 10 mg, Administered Twice Daily in Subjects With Multiple Sclerosis (ENHANCE)

The primary objective is to determine whether prolonged-release fampridine (10 mg twice daily) has a clinically meaningful effect on participant-reported walking ability over a 24-week study period. The secondary objectives are: to determine whether prolonged-release fampridine 10 mg taken twice daily (BID) has a clinically meaningful effect on dynamic and static balance, physical impact of multiple sclerosis (MS), and upper extremity function over a 24-week study period; to evaluate criteria for early assessment of response to fampridine that can predict clinically meaningful benefits in walking ability and balance; to assess the safety and tolerability of prolonged-release fampridine 10 mg twice daily over a 24-week treatment period.